Running length vs effective edge - conversion

[CFO]

Rocker - maybe. Magnetraction just slows you down, but we are going off topic...

There has to be someone from the industry on the website who knows the difference in derivation of effective edge and running length...

[vinman]

To me running length is measured from contact points at the tip and tail when the. Ski is flat. Effective edge would be measured from the contact points when the ski is up on edge in a turn.

They would very likely be very similar measurments

[CFO]

Hey Vinman,

I completely missed the point that RL is measured when ski is flat. My calculations are actually based on that assumption and yes, RL and effective edge should be very similar. Yet, if you look at manufacturer's quoted RL and effective edge, there is a significant difference...

This is what puzzles me.

[doughboyshredder]

if you read my post, and stopped trying to be a genius, maybe you'd figure it out.

Magnetraction slows you down. Yep. That's why the top pros use it in the halfpipe. Cause speed doesn't matter.

cfo just multiply running length times wtf to get your idea.

[CFO]

Whats up your arse, doughboy? you have your opinion, I have mine. Theres no need to get all worked up about it and get personal. My question is factual and it would help me a lot if someone actually knew the answer.

[doughboyshredder]

What's up my arse, is that I already posted your answer.

So, I have to ask, what is up your ass?

It is pretty basic. The flat part of the base between contact points is your running length. The effective edge corrsesponds to this, but is measured in such a way that depending on your sidecut radius it will be a slightly higher number than your running length.

I.E. no sidecut, ee equals running length. The smaller your sidecut radius the bigger your ee will be.

This isn't an opinion thing, and if you'd quit being a douche, you would understand that.

[doughboyshredder]

Whats up your arse, doughboy? you have your opinion, I have mine. Theres no need to get all worked up about it and get personal. My question is factual and it would help me a lot if someone actually knew the answer.

The effective edge measures the length of edge between the nose and tail of the board that is in contact with the snow. It is similar to running length, but measured along the curved edge rather than in a straight line, making it a slightly higher number.

this last explanation makes the most sense to me, and if that's what you're thinking then there would be a formula, but it would be dependent on the type and radius of the sidecut.

[CFO]

I understand what you are saying. I know what running length is and what effective edge is. But if you look at a company quoting running length only and a company quoting effective edge only, then how do you draw a comparison? Especially, they dont give you tip/tail length, so you're guessing really. I expected the difference to be indeed minor, but say Burton quote running length 40 mil shorter than ee. And thats for a snowboard. For a ski this difference will be even larger.

[vinman]

[quote="CFO"]I understand what you are saying. I know what running length is and what effective edge is. But if you look at a company quoting running length only and a company quoting effective edge only, then how do you draw a comparison? Especially, they dont give you tip/tail length, so you're guessing really. I expected the difference to be indeed minor, but say Burton quote running length 40 mil shorter than ee. And thats for a snowboard. For a ski this difference will be even larger.[/quote


Maybe because RL is a strait line and EE is an arc.....

[doughboyshredder]

For a ski this difference will be even larger.

Actually, since skis typically have a larger sidecut radius, then this difference will be even smaller.

vinman, thanks, that's what I was trying to say.

[nate]

Yes, there is a mathmatical way to compute effective edge based on running length and sidecut radius. Or vice versa. I couldn't tell you what it is. But it exists.

[nate]

Ok, so I thought about this some more and messed with some numbers. Taking the specs for the Line Anthem (symmetrical so it's easier) @178cm:

119-93-119
18.5m turning radius
1483mm "surface" (I interpret as running length)

The effective edge is 1485.28cm. Ie 2.28cm greater than the running length.


here's my math if you can follow it.
i tried to make it clear.

[CFO]

Hey Nate,

Thanks for taking time to explain. I used exactly the same logic (going through sine, not tan) and I get the same results. It seem that the issue is less relevant to skis than snowboards. The conversion does not work for any snowboard out there.

[endre]

i tried to make it clear.

hey that's a big-headed smiley you got there!

I am not shure if I understand the problem... effective edge is just another name for the length of the sidecut in a straight line, running length is the length of the camber. there is not necessarily any coherence.

[doughboyshredder]

The conversion does not work for any snowboard out there.

Why would you say this? You do realize that there are snowboards with large radius sidecuts, don't you?